In the process of shipping an item from one location to another, a protective packaging material is typically placed in the shipping case, or box, to fill any voids and/or to cushion the item during the shipping process. Some conventional commonly used protective packaging materials are plastic foam peanuts and plastic bubble pack. While these conventional plastic materials seem to adequately perform as cushioning products, they are not without disadvantages. For example, one drawback of plastic bubble film is that it usually includes a polyvinylidene chloride coating. This coating prevents the plastic film from being safely incinerated, which often creates disposal difficulties. Additionally, both the plastic foam peanuts and the plastic bubble pack have a tendency to generate a charge of static electricity attracting dust from the surrounding packaging site. Also, these plastic materials sometimes themselves produce a significant amount of packaging "lint." Such dust and lint particles are generally undesirable and may even be destructive to sensitive merchandise such as electronic or medical equipment.
But perhaps the most serious drawback of plastic bubble wrap and/or plastic foam peanuts is their effect on our environment. Quite simply, these plastic packaging materials are not biodegradable and thus they cannot avoid further multiplying our planet's already critical waste disposal problems. The non-biodegradability of these packaging materials has become increasingly important in light of many industries adopting more progressive policies in terms of environmental responsibility.
These and other disadvantages of conventional plastic packaging materials has made paper protective packaging material a very popular alterative. Paper is biodegradable, recyclable and renewable; making it an environmentally responsible choice for conscientious industries. Additionally, paper may be safely incinerated by the recipients of the products. Furthermore, paper protective packaging material is perfect for particle-sensitive merchandise, as its clean dust-free surface is resistant to static cling.
While paper in sheet form could possibly be used as a protective packaging material, it is usually preferable to convert the sheets of paper into a relatively low density pad-like cushioning dunnage product. This conversion may be accomplished by a cushioning conversion machine, such as that disclosed in U.S. application Ser. Nos. 07/840,306; 07/840,306; 07/712,203 (now U.S. Pat. No. 5,123,889); and Ser. No. 07/592,572. (These applications are all assigned to the assignee of the present invention.) Such a cushioning conversion machine converts sheet-like stock material, such as paper in multi-ply form, into cut sections of a relatively low density pad-like cushioning product. The stock material may consist of three superimposed webs or layers of biodegradable, recyclable and reusable thirty-pound Kraft paper rolled onto a hollow cylindrical tube. A thirty-inch roll of this paper, which is approximately 450 feet long, will weigh about 35 pounds and will provide cushioning equal to approximately four fifteen cubic foot bags of plastic foam peanuts while at the same time requiring less than one-thirtieth the storage space.
Specifically, the machine converts the stock material into a continuous unconnected strip having lateral pillow-like portions separated by a thin central band. This strip is connected or coined along the central band to form a coined strip which is cut into sections of a desired length. The cut sections each include lateral pillow-like portions separated by a thin central band and provide an excellent relatively low density pad-like product which may be used instead of conventional plastic protective packaging material.
The cushioning conversion machine disclosed in the above-identified applications includes a frame having an upstream end and a downstream end. (The terms "upstream" and "downstream" in this context are characteristic of the direction of flow of the stock material through the machine.) The frame is formed from a base plate, an upstream end plate, and a downstream end plate. The downstream end plate is generally rectangular and includes a relatively small rectangular outlet opening. The frame also includes a box-like extension removably attached to a downstream portion of the base plate.
The machine further includes a stock supply assembly, a forming assembly, a gear assembly, a cutting assembly, and a post cutting constraining assembly, all of which are mounted on the machine frame. In operation of the machine, the stock supply assembly supplies the stock material to the forming assembly. The forming assembly causes inward rolling of the lateral edges of the sheet-like stock material to form the lateral pillow-like portions of the continuous strip. The gear assembly pulls the stock material through the machine and also coins the central band of the continuous strip to form the coined strip. The coined strip travels downstream from the gear assembly and through the outlet opening in the end plate. The cutting assembly, which is mounted on the downstream side of the end plate, cuts the coined strip into sections of a desired length. These cut sections then travel through the post-cutting constraining assembly.
The post-cutting constraining assembly, which is of particular interest in the present application, is located downstream of the cutting assembly and is mounted on the box-like extension. The post-cutting constraining assembly is basically funnel-shaped and is positioned so that its inlet is aligned with the outlet opening of the end plate. A cut section will be urged or pushed downstream through the post-cutting constraining assembly by the approaching coined strip. As the cut section passes through the post-cutting constraining assembly, it is constrained circumferentially to improve its cushioning quality.
The post-cutting constraining assembly has proven to be a very advantageous feature in a cushioning conversion machine. However, in order to be effective, the cross-sectional geometry of the post-cutting constraining assembly must closely approximate that of a cut section. Moreover, as was explained above, it is the urging of the approaching coined strip which pushes the cut section through the post-cutting constraining assembly. Consequently, it is important for the cut section to be aligned both with the outlet of the end plate and with the inlet of the post-cutting constraining assembly. In other words, the cut section must have a smooth transition into the post-cutting constraining assembly.
In the above-identified applications, the cutting assembly includes a stationary blade and a moving blade, both of which are strategically positioned relative to the outlet opening. During operation of the cutting assembly, the moving blade travels between a rest position and a cutting position. More specifically, the moving blade will travel through one cycle of making a cutting stroke and a return stroke to the rest position. During the cutting stroke, the moving blade travels across the outlet opening and coacts with the stationary blade. For example, the moving blade can coact with the stationary blade in a "guillotine-like" fashion or, alternatively, coact with the stationary blade in a "scissor-like" fashion.
Applicants believe that the cutting assemblies disclosed in the above-identified applications adequately perform their cutting functions. Nonetheless, applicants also appreciated that, in certain situations, alignment problems might be created due to the action of the moving blade. Specifically, the action of the moving blade during the cutting stroke sometimes tends to misalign the cut section relative to the outlet opening and/or the inlet to the post-cutting constraining assembly. As the moving blade returns to the rest position, the cut section will sometimes "rebound" back into alignment. However, the cut section often remains at least partially misaligned even after the return stroke of the blade.
Accordingly, applicants developed the cutting assembly of the present invention to insure correct alignment of the cut section relative to the outlet of the end plate and the inlet of the post-cutting constraining assembly. Specifically, the cutting assembly includes an automatic alignment device which automatically "re-aligns" the cut section with the outlet opening and the post-cutting constraining assembly during the return stroke of the moving blade. In other words, the alignment device insures a smooth transition for the cut section from the outlet opening through the post-cutting constraining assembly. In this manner, the cut section steadily continues its downstream travel as it is pushed by the approaching coined strip.
More particularly, the present invention provides a cushioning conversion machine for converting sheet-like stock material into cut sections of a pad-like cushioning dunnage product. The machine comprises a frame, conversion assemblies which convert the sheet-like stock material into the cushioning dunnage product, and a cutting assembly which cuts the cushioning dunnage product into cut sections. The frame includes an outlet opening through which the cushioning dunnage product emerges. The cutting assembly, which is mounted downstream of the outlet opening, comprises a first blade and a second blade. The second blade is mounted on the frame in such a manner that it travels between a rest position whereat it is removed from the first blade to a cutting position whereat it coacts with the first blade to cut the cushioning dunnage product into a cut section. The cutting assembly further comprises an automatic alignment device which automatically aligns the cut section with the outlet opening when the second blade is moved from the cutting position to the rest position.
The machine may further comprise a post-cutting constraining assembly which circumferentially and longitudinally constrains the cut sections. The post-cutting constraining assembly, which is mounted on the frame downstream of the cutting assembly, includes an inlet which is aligned with the outlet opening. Thus, the automatic alignment device automatically aligns the cut section with the inlet when the second blade is moved from the cutting position to the rest position.
Additionally or alternatively, the cutting assembly may further comprise an automatic interruption switch which automatically temporarily stops the production of the dunnage product when the second blade is removed from the rest position. In the preferred embodiment, such an automatic interruption switch would be electrically connected to the pulling/connecting assembly (or the gear assembly) of the machine. Specifically, the automatic interruption switch would comprise a depressible button which allows operation of the pulling/connecting assembly when it is in a depressed condition and which interrupts operation of the pulling/connecting assembly when it is in a released condition.
The present invention provides these and other features hereinafter fully described and particularly pointed out in the claims. The following description and annexed drawings set forth in detail certain illustrative embodiments of the invention. These embodiments are indicative, however, of but a few of the various ways in which the principles of the invention may be employed.